Support for wildcard in pipeline

This patch will support for wildcard in pipeline.yaml so we
can exclude things like !storage.objects.*

This patch is dedicated to Fei Long Wang who triggered my thought on the
subject and proposed a first implementation.

docImpact
Fixes bug 1209128

Change-Id: I09a805ea7c9313b45152672a63981d5d4c263601

ceilometer/pipeline.py

@@ -16,6 +16,7 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import fnmatch
 import itertools
 import os
 import operator
@@ -241,14 +242,27 @@ class Pipeline(object):
 
     def support_meter(self, meter_name):
         meter_name = self._variable_meter_name(meter_name)
-        if ('!' + meter_name) in self.meters:
-            return False
-        if '*' in self.meters:
-            return True
-        elif self.meters[0][0] == '!':
-            return not ('!' + meter_name) in self.meters
+
+        # Special case: if we only have negation, we suppose the default it
+        # allow
+        if all(meter.startswith('!') for meter in self.meters):
+            default = True
         else:
-            return meter_name in self.meters
+            default = False
+
+        # Support wildcard like storage.* and !disk.*
+        # Start with negation, we consider that the order is deny, allow
+        if any(fnmatch.fnmatch(meter_name, meter[1:])
+               for meter in self.meters
+               if meter[0] == '!'):
+            return False
+
+        if any(fnmatch.fnmatch(meter_name, meter)
+               for meter in self.meters
+               if meter[0] != '!'):
+            return True
+
+        return default
 
     def flush(self, ctxt):
         """Flush data after all samples have been injected to pipeline."""

tests/test_pipeline.py

@@ -325,6 +325,37 @@ class TestPipeline(base.TestCase):
         self.assertTrue(pipeline_manager.pipelines[0].support_meter('b'))
         self.assertFalse(pipeline_manager.pipelines[0].support_meter('c'))
 
+    def test_wildcard_and_excluded_wildcard_counters(self):
+        counter_cfg = ['*', '!disk.*']
+        self.pipeline_cfg[0]['counters'] = counter_cfg
+        pipeline_manager = pipeline.PipelineManager(self.pipeline_cfg,
+                                                    self.transformer_manager)
+        self.assertFalse(pipeline_manager.pipelines[0].
+                         support_meter('disk.read.bytes'))
+        self.assertTrue(pipeline_manager.pipelines[0].support_meter('cpu'))
+
+    def test_included_counter_and_wildcard_counters(self):
+        counter_cfg = ['cpu', 'disk.*']
+        self.pipeline_cfg[0]['counters'] = counter_cfg
+        pipeline_manager = pipeline.PipelineManager(self.pipeline_cfg,
+                                                    self.transformer_manager)
+        self.assertTrue(pipeline_manager.pipelines[0].
+                        support_meter('disk.read.bytes'))
+        self.assertTrue(pipeline_manager.pipelines[0].support_meter('cpu'))
+        self.assertFalse(pipeline_manager.pipelines[0].
+                         support_meter('instance'))
+
+    def test_excluded_counter_and_excluded_wildcard_counters(self):
+        counter_cfg = ['!cpu', '!disk.*']
+        self.pipeline_cfg[0]['counters'] = counter_cfg
+        pipeline_manager = pipeline.PipelineManager(self.pipeline_cfg,
+                                                    self.transformer_manager)
+        self.assertFalse(pipeline_manager.pipelines[0].
+                         support_meter('disk.read.bytes'))
+        self.assertFalse(pipeline_manager.pipelines[0].support_meter('cpu'))
+        self.assertTrue(pipeline_manager.pipelines[0].
+                        support_meter('instance'))
+
     def test_multiple_pipeline(self):
         self.pipeline_cfg.append({
             'name': 'second_pipeline',